Spark plug



March 9,1926. 1,576,344

S. MACPHERSON ET AL SPARK PLUG Filed June- 5 1925 INVENTORJ:

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' cations can be resorted to which come, with;

Patented Mar. 9, 1926.

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STUART MACPHEESON AND JAMES C. PORTER, OF PITTSBURGH, PENN$YLVANIA.

SPARK PLUG.

Application filed June 5, 1325. Serial No. 35,127.

To all ill/L07, it may concern.

Be it known that we, STUART Mauritian- SON and-JAMES C. PORTER, citizens of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in. Spark Plugs, of which the following is a specification;

This invention relates to a spark plug, and has for its object to provide, in a manner as hereinafter set forth, a plug that requires but little or no attention and with perfect ignition always present.

A further object of the invention isto provide, in a manner as hereinafter set forth, a spark plug including a plurality of auxiliary electrodes of spherical form shiftably mounted upon a base of conducting material and coacting with the central electrode of the plug in a manner to provide for the spark gap to remain constant, and to provide for the electrical discharge from the central electrode to; contact with and scatter over the peripheral surface of the auxiliary electrodes, thereby producing a spark of greater intensity than that obtained in the plugs now generally used, and which furthereliminates the extra expense of applying diiiferent types of unit intensifiers.

A further object of the invention is to provide, in a manner as hereinafter set forth, a spark plug having means to produce a circle of flame which will ignite weak gases under the most severe conditions.

A further object. of the invention is to prdvide, in a manner as hereinafter set forth, aspark plug constructed in a manner to overcome the collecting of carbon to prevent fouling of the plug.

Further objects of the invention are to provide, in a manner as hereinafter set forth, a spark plug, which is simple in its construction and arrangement, strong, durable, thoroughly efficient in its use, of materially greater life than the plugs now in general use, readily assembled, and comparatively inexpensive to manufacture.

With the foregoing and other obyects 1n described and illustrated in the accompanying drawings, wherein is shown an'embodiment of the invention, but it is to be understood that changes, variations and modifiin the scope of the claims hereunto appended.

In the drawings where like reference characters denote corresponding parts throughout the several views: I

Figure 1 is a'vertical sectional view of a spark plug, in accordance with this invention.

Figure 2 is an inverted plan.

Figure 3 is a section on line 33, Figure 1.

material and provided. with a lengthwise extending passage 2, which merges into a lGDgtlHVlSS extending socket 3 of greater diameter than the passage 2, thereby providing a shoulder 4. The passage 2, at one end, opens at the outer end of the plug body 1, and the socket 3 opens at the innerend of the plug body 1, and the latter is provided intermediate its ends with a laterally extending annular boss 5, having a downwardly inclined outer edge 6 and an inwardly curved inner edge 7. The edges 6 and "I provide shoulders. V

I The shell of the plug, which is formed of conducting material, is indicated at 8, and has its outer face formed with an annular shoulder 9, uponwhich is seated a washer 10, and engaging thelatter is the inner edge or shoulder 7 of the plug body 1. The inner face of the shell 8, outwardly with respect to the shoulderl), is provided with threads 11, and the shell 8 at the inner portion thereof is formed with peripheral threads .12.

The plug body 1 extended in the shell 8 and has theinner end thereof terminating ata point removed with respect to the inner end of the shell 8, and said plug body 1 is removably secured in the shell 8, through the medium of a peripherally threaded gland 18, threadedly engaging awiththe threads 11' of the shell 8. Interview, the invention consists of the; novel construction, combination and arrangement of parts, as hereinafter more specificallyposed between the inner end of the gland 13 and edge 6 of the boss 5 is a washer lat.

Extending through the plug body 1 is centralelectrode'15, having a reduced inner portion 16 and a collar 17 on said reduced portion. The central electrode has the outer end terminal portion thereof pev riphl'erally threaded, as at 18, and mounted number.

thereon is a securing nut 19, washer 2. and a binding nut 21. Supported on the collar 17 is a Washer 22 which abuts against the shoulder a. The washer 2O abuts against the outer end ofthe plug body and is engaged by the securing nut 19. ;The collar 17, washers and 22, nut 19 and shoulder 4ifixedly secure the central electrode 15 to the plug body 1.

The nut 21, in connection with. the nu 19, clamps a circuit'comiection, not shown, to the electrode 15. The reduced portion 16 of the electrode 15 projects inwardly from the inner terminus of the shell 8. The elements aforesaid are of known construction. l

The inner terminus of the inner face of the shell 8 is bevelled to provide an annular shoulder 23, and formed integral with the innot end edge of the shell 8 is a cage or sleeve 24 of a thickness less than the thickness of said shell 8. The inner face of the sleeve 24 is flush with the lower terminus of the shoulder 23.

The body portion of the sleeve 2a is cut away intermediate its outer and inner ends to provide a series of concentrically arranged openings 25, 26 and 27, and the inner face of the sleeve 2% below said openings is prov'ded with a shoulder 28, and, arranged within said'sleeve 24: as well as abutting against the shoulder 28 is a cup-shaped member 29 swaged as at 30, for fixedly securing it to the sleeve 24. The top edge of the member 29 is bevelled, as at 31, and the bottom 32 of said member 29 is provided with. a series of equally spaced circular openings 33, as shown four in Formed integral with the inner face of the bottom 32, at the axis thereof, is a conoidal-shaped protuberance 34:, of a lengtl-i less than the height of the member 29 and which, coacts with the edge 31 to provide a ball race for av pair of spherical auxiliary electrodes 35 of greater diameter than either of the openings 33 and of a diameter to project above the. edge. 31 and in close proximity to the innerend, of the central electrode 15. electrode 15v is disposed to align with the axis of the protuberance 34:. The distance between theelectrode 15 and the inner face ofthe shell 8 is less than the diameter of an, auxiliary electrode 3 5, and the. shoulder 23 eonstitutesa stop. to arrest the. outward movement of an auxiliary electrode.

The auxiliary electrodes shift around the ball race formed by the. protuberance 3-1- and edge 31 and coact with the electrode. 15 to provide .the spark; between the inner terminus of the electrode 15 and the periphery of the auxiliary electrodes.

In the. modified form. shown in Figure 4, the cup-shaped niember 30 is dispensed with,

The inner end of the The gap is formed and in lieu thereof the ball race and protuberance. are integral parts of a cage or sleeve which projects from the inner terminus of the shell 8. The cage or sleeve, which referred to generally by the reference character 36, has a cup-shaped inner portion 37 of greater thickness than its outer portion 38. The inner portion 37 projects inwardly with respect to the inner face of the outer portion 38, and the projecting part of the inner portion 37 is bevelled, as at 39. The inner end of the portion 37 is provided with openings 40, corresponding to the openings 33, and said-inner portion 37 is formed with a conoidal-shaped protuberance 41 corresponding to the protuberance 34-. The bevelled inner end 39 and protuberance ll cou to provide a ball race for the auxiliary electrodes Otherwise than that as stated, the construction shown in Figure t is the same as that shown in Figure 1.

The construction set forth provides a spark plug wherein the electrical discharge is. not at the same point of contact at all times, with respect to the central; and 21,112;- il-iary electrodes. The spherical auxiliary electrodes shifting on the ball, race and the arrangement of said race and auxiliary electrodes with respect to; the central electrode, provides for the spark gap to remain constant, allowing of the electrical discharge from the central electrode to: come. in contact with the auxiliary electrodes and scattered over, the spherical surfaces of these latter which produces an intensified spark matcrially greater than, that obtained 1n the types of plugs now. generally used, and

furthermore eliminates extracxpense of applying different types of unit intensifiers.

Owing to the construction and arrangement of the auxiliary electrodes, the collection. of carbon. is overcome as the vibration of the motor from the motion of its reciprocating parts causes. the spherical electrodes to. shiftin the ball race, thereby overcoming the collecting of carbon as carbon will not collect on a moving part. auxiliary electrodes are constantly moving, they, as Well as the race therefor, are kept clean, which overcomes the fouling of the plug, and under such conditions insuresperfeet ignition. Therefore, the disadvantages of carbon formation which are common to types. ofplugsnow generally used, are eliminated.

The sleeve 24: or 36 and the parts carried thereby are so designed that the large open ings in. the-sides of the sleeve and under-. neath the ball race provide; that when the electrical discharge takes. place, due to the shape of theauxiliary electrodes, }the mechanical effect of the discharged matter is scattered presenting. a large flame area to the gaseslfor ignition. In this manner a higherdegree of ignition is effected, and, further- As. the

more, the auxiliary electrodes produce what may be termed a circle of flame which will ignite weak gases under the most severe conditions.

It is thought that the many advantages of a spark plug, in accordance with this invention, can be readily understood, and although the preferred embodiment of the invention is as illustrated and described, yet it is to be understood that changes in the details of construction can be had which will fall within the scope of the invention as claimed.

What we claim is 1. In a spark plug a peripherallythreaded shell, a central electrode extended from the inner terminus thereof, a cylindrical cage extended from the inner edge of the shell and provided with a row of circumferentially extending rectangular openings above the transverse median of the cage, a cup-shaped member secured within the sleeve below said openings and having its bottom flush with the inner end of the cage and formed with a series of openings, said member having centrally disposed means carried by the uppertace of the bottom thereof, extending towards the openings in the cage and coacting with the edge of said member to provide an annular ball race, and a plurality of auxiliary electrodes of spherical contour shiftable in and projecting from said race and spaced from said central electrode.

2. In a spar plug a peripherally threaded shell, a central electrode extended from the inner terminus thereof, a cylindrical cage extended from the inner end of said shell and having a closure at its inner end formed ball race spaced from said closure, and a plurality of auxiliary electrodes of spherical contour shiftable in and projecting from said race and associated with said central electrode. V

In testimony whereof, we aiiix our signatures hereto.

STUART MACPHERSON. JAMES C. PORTER. 

